PROJECT SUMMARY/ABSTRACT In the past decade, Puerto Rico has experienced rapid population aging, financial collapse, mass outward migration of younger people, and then Hurricane Maria. Now is an ideal time to build on the only population- based cohort of older adults in Puerto Rico, unique in having data on health and function prior to these major events. Households across Puerto Rico were visited to identify the first island-wide sample of adults age 60+ years for the Puerto Rican Elderly: Health Conditions (PREHCO) study. A wide range of measures relevant to health and aging, including in-home testing of cognitive and physical function, was collected at baseline (2002/2003) and four years later (2006/2007). We propose to gather two new waves of data related to aging, stress and health in a sample of approximately 1,000 PREHCO survivors. The current project will a) extend PREHCO follow-up to between 16 and 20 years after baseline; b) examine life course predictors of major aging outcomes, namely cognitive impairment, disability, and mortality; c) collect data on hurricane-related stressors and mental health; d) add hair cortisol as a marker of chronic hypothalamic pituitary adrenal (HPA) axis activation; and e) add cognitive and proxy informant measures that align with the Health and Retirement Study (HRS). Our project will enable the following specific aims: Aim 1. Examine longitudinal life course biopsychosocial predictors of cognitive health, cortisol levels, mental health, disability, and mortality 16-20 years after baseline. Aim 2. Examine cross-sectional associations between stressors, resilience-enhancing factors, perceived stress, cortisol, and health, as well as changes in health two years later. Aim 3. Increase utility of PREHCO for cross-cultural comparisons. Puerto Rico is an important part of the U.S. that has largely been omitted from U.S. population-based studies of aging. PREHCO participants are now age 76+ years and given accelerating mortality rates for this age group, our proposal to gather two new time points of follow-up data for PREHCO represents a time-limited opportunity to add to our knowledge about aging, stress, and health in an understudied and potentially vulnerable population.